Over the past several decades the technology of electronics has evolved from the vacuum tube to the discretely employed transistor and then to the integrated circuit (IC). The latter integrated circuits are generally referred to as "chips". Integrated circuit technology has advanced to custom circuit integration or microelectronics involving a science generally referred to as "very large scale integration" (VLSI). This technological evolution, for the most part has occurred in the domain or world of digital microelectronics, as opposed to the analog world of electronics. Technological evolution in the digital world has generated very high component densities in silicon, providing circuits evidencing not only improved operational capabilities, but also advantageously providing lower costs for the functions achieved. In effect, the components of the digital circuit have been scaleable to smaller and smaller levels to the extent that the power of digital processing has been observed essentially to double about every eighteen months. Digital circuits are readily programmable, an aspect of their nature which has greatly expanded the availability of digital electronics technology to a wide range of disciplines. Thus, the scientist or engineer trained in non-electronic disciplines may enjoy the capability of using high level programming language to apply digital electronics to non-electronic technologies.
The analog world of electronics has not grown nor developed apace, even though commentators have observed that it is an analog world that we live in. For example, the following commentary has been made:
However since we live in an analog world, we cannot avoid processing analog signals and in many cases it is more natural to use analog, rather than digital signal processing. PA1 S. Sakurai and M. Ismail. "Low-Voltage CMOS Operational Amplifiers: Theory, Design, and Implementation". 1995, Kluwer Academic Publishers.
Typical analog electronics involve the sensing of or reaction to some physical phenomena in the generation of a corresponding electrical signal. Conversely, analog electronics may respond to some form of electronic command signal to drive an actuator, typically resulting in some form of physical result such as the motion of a motor or loudspeaker. These tasks require the use of amplifiers such as the ubiquitous operational amplifier, filters, buffers, comparators and the like. The design of such analog circuits usually requires an analog specialist; is time consuming and costly. Components forming analog circuits such as capacitors and resistors are not uniformly precise, thus tuning, noise rejection and like affectations generally will hinder the progress of circuit development. Re-design efforts in perfecting circuits are not uncommon. A programmability of analog circuits would be most beneficial, such that the designer can quickly and efficiently alter the circuits as the physical phenomena with which they perform is more understood. To the present, however, this type feature has only been available to the extent of switching components such as capacitors or resistors in and out of the analog circuits, for example, to adjust gain. Because the number of such components is finite, the adjustments achieved necessarily are gross without the availability of vernier tuning.
Very often, the analog circuits are combined with digital circuits, i.e., in integrated circuits referred to "mixed mode" devices. The interface between analog and digital regimes is through analog to digital (A/D) or digital to analog (D/A) converters. Most commonly, these devices perform with multi-bit parallel words, i.e., sixteen, thirty-two or sixty-four bit word systems, the multiple lines of which consume a substantial area of silicon on a chip. There are, however, several methods of analog to digital or digital to analog conversion, i.e., Sigma Delta converters which, for example, combine oversampling with decimation filtering in an input analog to digital configuration. The bit stream outputs of those input features then are combined with mu and A-law encoder functions the development of which has been based upon what amounts to decades of investigation into specific areas of use, i.e., speech, and video systems. These integrated circuits conventionally are referred to as codecs. Their output from digital to analog performance typically utilizes an expanding interpolation filter, a Sigma Delta digital to analog converter and filtering. For the present, codecs are application specific.
A more common combination of analog and digital circuitry is through the utilization of both analog to digital and digital to analog converters in conjunction with a digital signal processor (DSP). The DSP is a rather large integrated circuit requiring the utilization of a microcontroller and programming with a complexity again requiring the services of an electronic specialist. Generally, their circuits will not be contained in a single chip and their programmability is limited to the digital (DSP) regime. Of course, cost in labor and manufacture follows complexity in the world of analog and digital combinations.
An integrated circuit having the ability to fine tune analog input paths and output paths which is programmable, using universally understood high level programming language would be well received in the technical community. Such a circuit would permit scientists and engineers within a wide variety of disciplines other than digital or analog electronics to develop systems and products with relative facility and would hold promise to promote the development of new products and systems.